Self-playing stringed instrument



April 6 1926.

1,579,792 H. K. SANDELL SELF PLAYING STRINGED INSTRUMENT Filed August 17 1922 4 Sheets-Sheet 1 mum;

April 6,1926. 1,579,792

H. K. SANDELL SELF PLAYING STRINGED INSTRUMENT Filed August 17. 1922 4 Sheets-Sheet 2 210622707.- [Ml/d4 4 Sheets-Sheet 5 IIMII H. K. SANDELL SELF PLAYING STRINGED INSTRUMENT Filed August 17; 19 22 April 6 1926.

April 6,1926.

H. K. SANDELL SELF PLAYING STRINGED INSTRUMENT Filed August 17 1922 4 Sheets-Sheet 4 flew WW Patented Apr. 6, i 1926.

UNlTED STATES PATENT OFFICE...

HENRY K. SANDELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO MILLS NOVELTY COM- IPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SELF-PLAYING STRING-ED INSTRUMENT.

Application filed August 17, 1922. Serial No. 582,458.

To all whom it may concern:

Be it known that I, HENRY K. SANDELL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Self-Playing Stringed Instruments, of which the following is a specification.

The present invention relates to improvements in self-playing stringed instruments, and will be fully understood from the fol lowing description, illustrated in the accompanying drawings, in which- Figure 1 is a broken side elevation showing a device embodying the present inven-.

tion;

Fig. 2 is a plan view of the device illustrated in Fig. 1;

Fig. 3 is a vertical sectional view through the bow motor; 7

Fig. 4 is a horizontal sectional view through the bow motor on the broken line 44 of Fig. 3;

Fig. 5 is a vertical sectional view on the line 5-5 of Fig. 3; and i Fig. 6 is a diagrammatic view illustrating the circuits employed in connection with the present embodiment of the invention.

Referring more particularly to the drawings, the numeral 10 indicates an instrument, which may suitably be of the violin type, and which is supported by any suitable means, such as brackets, of which one is shown at 11. To one side of the violin, and extending substantially parallel to the strings 12 is provided a supporting frame work 13 in which are mounted the lingering levers 1-1 and the electromagnets 14 for actuating the same. 1

Above each string 12 is a bow member or sounder 15, preferably formed of nested conical celluloid shells, these sounders being secured to the ends of the bow shafts 16, which extend in a direction substantially longitudinally of the strings 12. These bow shafts 16 pass through a journal or hearing formed in the sleeves 18 which partially surround the worm 19, the sleeves 18 being rotatable for a limited distance upon the worm gear 19. At their ends the bow shafts 16 are provided with gears 20 which mesh with and are driven by the worm 19. The worm 19 is journaled in bearings suitably provided in a housing 21 supported on the bow motor casing, as hereinafter more fully described.

with the rotor 27 of the A. C. induction motor 28, which is housed in a casing 29 supported on the standard 30. The rotor 27 is of the induction motor type, provided with a squirrel cage 29 The stator 80, which is formed of laminated sheets of a suitable iron, is provided with the teeth 32 which form .the poles of the motor. The stator teeth 32 are divided into quadrants, each containing an equal number of teeth, the quadrants being separated by theteeth 33. A set of four-pole windings, connected: in series shown in Fig. 6, are provided, these windings passing around the teeth 32 of each quadrant and being separated by the teeth A second set of bipolar windings 35 are provided, likewise connected in series, these windings each passing around the teeth of two sets of successive quadrants and the included tooth 33 and being spaced apart by the alternate teeth The four-pole windings are preferably formed of a greater number of windings of smaller wire than the bipolar windings. A third set of windings S6 is provided within the bipolar windings, these windings each passing around one of the teeth 33 and an equal number (in the form illustrated, one) ofthe teeth 82 on each side thereof. The windings 36, which are out of phase with the remaining windings, are likewise connected in series with each other.

By the use of the windings described, the speed of rotation'ofthe bow shafts and the consequent volume of tone may be readily controlled. The windings 36 may be employed together with the other windings 85 as starting windings for the motor. normal operation, a controlled speed of rotation of the bow shafts is secured by means of the four-pole windings 34, the polarity of which is then caused to be dominant. A more rapid rate of rotation is secured by passing the current through the bipolar windings alone. It a slower rate of rotation and a lower volume of tone are desired, the phase windings 36 are placed in shunt with the other windings, through which current flows in series as in normal operation.

The operation of the device .is more clearly illustrated by Fig. 6, which shows diagrannnatically the electrical interconnec tion of the various parts, which are here given the same numerals as in the preceding figures of the drawing.

Two main lead lines 40 and 41 are provided for the operating current, which in the present instance, is an alternating current. The normal operating current, for rotation of the'bow shafts at a normal rate to produce a normal volume of tone, the current connection is from line 40 through the branch line 42 to the tour-pole coils 34, through which the current passes in series. From the four-pole coils 34 the current passes through the connection 44 to the bipolar coils 35, through which it passes in series. From the bipolar coils 35, the current passes directly into the lead line 41. As the bipolar coils 35 are constructed or fewer coils than the larger wire and of tourpole coils 34, the current produced by the latter is dominant and a normal rate of rotation is produced.

In order to produce a louder tone, suitable means are provided for increasing the rate of rotation of the motor. For example, the current may pass from the line 40 into the contact roll 45. A perforated notesheet 46 passes over this contact roll. When a suitable perforation is provided in the note sheet, contact is made between the roll 45 and the contact member 47, and current then passes through the line 48 which is directly connected to the connection 44 between the four-pole coils 34 and the bipolar windings 35. Current then passes through the two bipolar windings 35 in series and thence to the line 41. The tour-pole windings 34 are thus shunted out of the circuit and the po larit-y of the stator of the motor is deter mined by the bipolar windings 35, with a consequent increase in speed of the rotor. In manual operation, the same effect may be produced by passing the current from the line 40 through the line 41*, the pedal contacts 46 and 47 and the connector 48, which is directly connected to the line 48 leading to the bipolar windings 35.

For slower rotation of the rotor of the motor and a lower volume of tone, current passes from the line 40 into the contact roll 45, through contact 49 when a suitable perforation is provided, thence through connector 50 to the split phase windings 36,

through which it passes in series. From the split phase windings 36 the current passes through a connector 51 to the line 41. Instead of employing the contact rollers 45 and the contact 49, this circuit may likewise be closed through the line 40, the pedal 45, pedal contact 49 and line 50. It will be noted that there is always a connection through the tour-pole windings 34 and through the bipolar windings 3;) in series at all times, unless modified by the action of the control contacts. Consequently, when current passes through the contact roll 45 and the contacts 49 or through the corresponding pedal contacts just referred to, the circuit through the split phase windings 36 is in shunt with the circuit through the windings 34 and Consequently, current at this time passes through all of the windings, that through the split phase windings being in shunt and the rate of rotation of the rotor is materially decreased. The note playing circuits are controlled independently of the circuits through the windings of the motor controlling its speed. For eX- ample, when contact is made between the contact roll 45 and the note playing contactmember 52, current passes through the connection 53 to the fingering magnet 14 thence through contact 54 to the bow shaft depressing electromagnet 25 and from this electromagnet through the. connection 55 to the line 41. This circuit operates without affecting the circuit through the bow motor.

Although the present invention has been descriheo in connection with the specific details of a device embodying the invention, it is not intended that these details shall be regarded as limitations upon the scope of the invention, except in so far as included in the accompanying claims.

I claim:

1. In a self-playing musical instrument,

a stringed instrument, sounders normally out of engagement with the strings thereof, means for imparting continuous movement to said sounders, said, means including an induction motor having a plurality of sets of windings adapted to impart different rates of speed thereto, means for passing alternating current selectively through the windings of the motor to determine the speed thereof, and means for engaging the sounders with the strings of the instruments, said means being actuated by circuits independent of the circuits through the motor.

2. In a self-playing musical instrument, a stringed instrument, Sounders normally out of engagement with the strings there-of, means for imparting continuous movement to said sounders, said means including an induction motor having a plurality of sets of windings, means for passing alternating current through certain oi said windings continuously to produce continuous movement of the sounders at a determined rate, means for engaging the sounders with the strings of the instrument, circuit-control means independent of the circuit through the motor to actuate the means for engaging the sounders with the strings, and additional means independently controllable for varying the circuits through the motor to vary the speed of rotation thereof.

3. In a self-playing musical instrument, a stringed instrument, sounders normally out of engagement with the strings thereof; and means for imparting continuous movement to said sounders, consisting of an alternating current motor comprising a squirrel cage rotor, a stator having individual sets of four-pole windings, bipolar windings and split phase windings, means for passing current through the four-pole windings and bipolar windings in series, means for cutting out the tour-pole windings to impart an increased rate of rotation to the rotor, and means for passing a shunt current through the split phase windings to decrease the speed of rotation of the rotor; and means for engaging the sounders with the strings of the instruments, said lastmentioned means being actuated by circuits independent of the circuits through the motor.

4. In a self-playing musical instrument, a stringed instrument, sounders normally out of engagement with the strings thereoi; and means for imparting continuous movement to said Sounders, consisting of an alternating current motor comprising a squirrel cage rotor, a stator having individual sets of tour-pole windings, bipolar windings and split phase windings, means for passing current through the four-pole windings and bipolar windings in series, means for cutting out the four-pole windings to impart an increased rate of rotation to the rotor, and means for passing a shunt current through the split phase windings to decrease the speed of rotation of the rotor; automatic means controlling the circuits of said Windings; and means for engaging the soundcrs with the strings of the instruments, said lastmentioned means being actuated by circuits independent of the circuits through the motor.

5. In a self-playing musical instrument, a stringed instrument, sounders normally out of engagement with the strings thereof; and means for imparting continuous movement to said sounders, consistsing of an alternating current motor comprising a squirrel cage rotor, a stator having inclividual sets of four-pole windings, bipolar windings and split phase windings, circuits for passing current through the four-pole windings and bipolar windings in series, for cutting out the four-pole windings to impart an increased rate of rotation to the rotor, and for passing a shunt current through the split phase windings to decrease the speed of rotation of the rotor, said circuits including av contact roller, coacting circuit-controlling contacts, and an interposed perforated music-sheet; and means for engaging the sounders with the strings of the instruments, said last-mentioned means being actuated by circuits independent of the circuits through the motor.

(5. In a self-playing musical instrument, a stringed. instrument, sounders normally out of engagement with the strings thereof; and means for imparting continuous movement to said sounders, consisting of an alternating current motor con'iprising a squirrel cage rotor, a stator having individual sets of fourpole windings, bipolar windings and split phase win-dings, circuits for passing current through the four-pole windings and bipolar windings in series, for cutting out the four pole windings to impart an increased rate oi. rotation to the rotor, and for passing a shunt current through the split phase windings to decrease the speed of rotation of the rotor, said circuits including a contact-roller, coacting circuit-controlli11g contacts, an interposed periforated music-sheet, and also manually actuated circuit controlling devices; and means for engaging the SOUHLlClS with the strings of the instruments, said lastinentioned means being actuated by circuits indepmidont of the circuits through. the 1notor.

l-IENRY K. SANDELL. 

